The invention involves a coupling device for a wind power plant with a rotor shaft that carries at least one rotor blade of the wind power plant, a gear shaft running coaxially to the rotor shaft, and a coupling device coupling the rotor shaft to the gear shaft.
In modern wind power plants, the rotor rotation is transferred via the rotor blades, possibly via a rotor shaft that carries a hub affixed to them, to the input shaft of a gear, whose output shaft is connected to a generator for power generation. In the process, the gear and the generator are usually housed in a machine housing that is set in bearings so that it can rotate on a tower of the wind power plant. The height of this tower can be 100 m or more.
If during the operation of the wind power plant, malfunctions occur in the area of the gear and/or the rotor shaft and/or the rotor bearings, the rotor shaft must be separated from the input shaft of the gear. For this reason, it is necessary that the coupling device coupling the rotor shaft to the gear shaft is designed so that the gear shaft can be separated from the rotor shaft quickly and easily. Furthermore, this coupling device must also make possible a malfunction-free transfer of the bending moment and the torque from the rotor shaft that has a diameter of one meter or more to the gear shaft. In known coupling devices for wind power plants, this transfer of the bending moment and torque is achieved using so-called tension sets with which the gear shaft constructed as a hollow shaft is pressed in the radial direction onto the rotor shaft that is inserted into the gear shaft. However, the solution of the non-positive connection between the rotor shaft and the gear shaft caused by these tension sets presents problems in many cases, because the individual elements of the tension sets tighten during the operation of the wind power plant. Furthermore, when using these tension sets, it is considered problematic that to separate the gear from the rotor shaft, at first the gear shaft must be separated from the rotor shaft in the horizontal direction, which presents large problems for rotor shafts with a diameter of one meter or more, and the rotors affixed to them with a diameter of 70 m or more, and the correspondingly dimensioned gear shafts.
To solve these problems, torque transfer devices have already been proposed for wind power plants, in which the end of the gear shaft faces the rotor shaft has a flange-type radial expansion and the coupling of the gear shaft to the rotor shaft is made using bolts that engage in an end face of the rotor shaft that faces the gear shaft and pass through this flange-type expansion. In the process, the rotor shaft of the known torque transfer devices can also have one or more receptacle spaces to receive a connection element for the rotational non-positive connection of the rotor shaft with the gear shaft, whereby corresponding receptacle spaces are also provided in the gear shaft. With this device, a separation of the gear from the gear shaft can be achieved without horizontal shifting of the gear shaft relative to the rotor, whereby the assembly and/or the replacement of the gear parts of the rotor and the rotor bearing is clearly simplified. However, it has turned out that the separation of the connection elements used in the receptacle spaces, and designed, for example, in the form of feather keys, present problems in many cases, especially after longer operating times of the wind power plant, which in turn leads to problems in the separation of the gear and/or the gear shaft from the rotor and/or rotor shaft.
In view of this problem in the state of the art, the purpose of the invention is to prepare a coupling device for a wind power plant of the type named above, which allows an additional simplification of the maintenance work as well as simple assembly.
According to the invention, this purpose is achieved by a further development of the known coupling devices, which is essentially characterized in that the coupling device has at least one connection element, which can be detachably affixed on the rotor shaft to an attachment element designed to create a positive locking connection, and one coupling element that is designed to create a friction-fit connection between the connection element, on the one hand, and an additional connection element and/or gear shaft, on the other hand.
This invention originates from the discovery that the problems in the state of the art explained at the beginning can be solved when the coupling of the rotor shaft to the gear shaft is done in at least two stages, whereby at first via a positive locking connection that can be impinged with large forces but can be detached again only with difficulty, a connection element is coupled to the rotor shaft, which is itself coupled to the gear shaft via a friction-fit connection that can be easily detached but generally can only be impinged with small forces. In the process, the coupling of the connection element to the gear shaft can, if necessary, be made via one or more additional connection elements. In order to detach the gear shaft from the rotor shaft, it is only necessary to detach the friction-fit connection, which usually does not cause any problems, whereas a detachment of the positive locking connection is still necessary to replace the roller bearing of the rotor shaft, which, however, is not performed on-site. In this way, maintenance and repair work is made considerably easier. Furthermore, the arrangement of the coupling device according to the invention also makes possible an especially easy assembly of the wind power plant, because at first the rotor bearing can be shoved over the rotor shaft, and only after that must the connection element be affixed to the attachment element in a positive locking manner on the rotor shaft.
To further simplify the assembly and maintenance work, it has proven to be especially favorable if the additional connection element that is connected in a friction-fit manner to the connection element is affixed to at least one additional attachment element designed to create a positive locking connection on the gear shaft. In this case, during the assembly, at first the gear bearing can be shoved on the gear shaft and only after that, the attachment of the additional connection element to the gear shaft and the friction-fit connection of the individual connection elements to each other are done.
In regard to the prevention of an excessive loading of the friction-fit connection during the transfer of large torques, it has proven to be especially favorable if at least one coupling element is arranged in the radial direction outside of the sheath surface of the rotor shaft so that even during the transfer of large torques, because of the comparatively large separation distance of this coupling element from the rotational axis, only small forces act on this coupling element. In the embodiment form of the invention last described, the connection element functionally has a flange that is essentially rotationally symmetric and is attached to the end face of the rotor shaft that becomes flush at its end that faces the gear shaft. The flange has a larger diameter than the rotor shaft.
In order to create a positive locking connection between this connection element and the rotor shaft, an attachment element is used in the form of a clamping sleeve that passes through the connection element and is inserted into the end face of the rotor shaft that faces the gear shaft. The additional connection element, also designed functionally in the form of a flange that is essentially rotationally symmetrical and has a larger diameter than the rotor shaft and/or the gear shaft, can also be affixed in a positive locking manner on the gear shaft to a clamping sheath that passes through this connection element and is inserted in the end area of the gear shaft that faces the rotor shaft and is preferably radially expanded.
If at least one clamping sheath inserted into the end face of the rotor shaft runs coaxially to a clamping sheath that is inserted into the end area of the gear shaft is designed in order to create a friction-fit connection between the rotor shaft and the gear shaft, and is functionally designed in the form of a bolt that is inserted into the rotor shaft or into the gear shaft, a pre-tensioning of the connection between the rotor shaft, the connection elements, and the gear shaft can be created using an additional coupling element that passes through this clamping sheath. Using this additional coupling element preferably designed in the form of a bolt, the bending moments can also be transferred from the rotor shaft to the gear shaft, in order to, in this way, unload the coupling elements which might be displaced radially to the outside. These coupling elements can also be designed in the form of coupling bolts, in particular, screwed bolts, with bolt axes running approximately parallel to the longitudinal axis of the rotor shaft, whereby at least one of the coupling elements that is displaced radially to the outside goes through the connection element and/or the additional connection element.
In regard to maintaining an introduction of force that is as symmetrical as possible, while simultaneously ensuring a reliable torque transfer, it has proven to be especially functional if the coupling device has a plurality of coupling elements preferably arranged distributed at uniform distances in the circumferential direction of the rotor shaft, each of which can be arranged at the same radial distance from the rotational axis of the rotor shaft.
In order to prevent the transfer of a bending moments to the coupling elements used for the torque transfer, it has proven to be functional if the connection element and/or the additional connection element is made of a weaker material and/or can be more easily deformed than the rotor shaft, the gear shaft and/or the attachment bolts, because in this construction, bending moments are first to be received by the shafts and/or additional coupling elements and lead at first to a deformation of the connection elements prior to their transfer to the coupling elements. In the process, an easier deformability can not only be achieved by a corresponding selection of materials, but also by a corresponding geometric design of the connection elements. This geometric design can make use of profilings of the connection elements and/or target bending points in the connection elements.
In the performance of repair and/or maintenance work on a wind power plant, the rotor must be fixed in order to reduce the risk of injury during repair and maintenance work. For this purpose, the coupling device of the device according to the invention has, in a preferred embodiment form of the invention, a stopping device to stop the rotor shaft and thus also the rotor blades carried by it. This stopping can be achieved using a radial and/or axial positive locking.
Even though consideration is given to the implementation of stopping arrangements, with which the rotor can be stopped in any desired rotational position, it has proven to be especially favorable for the purpose of making easier the maintenance work by creation of defined geometric relationships, if the stopping device has at least one stopping element to stop the rotor shaft in at least one prespecified rotational position. This stopping element can contain at least one stopper opening which faces radially to the outside relative to the rotor shaft and in which a stopping bolt is inserted to stop the rotor.
To maintain as symmetrical an overall arrangement as possible, the stopping arrangement functionally has a stopper ring that surrounds the connection element and/or the additional connection element and preferably is affixed to the connection element that is detachably affixed to the rotor shaft. In this preferred stopping arrangement, the rotor shaft can be stopped without impairment of the detachment of the gear shaft from it. With a stopper ring that surrounds the connection element, a stopping of the rotor shaft can be implemented in a plurality of prespecified rotational positions, if the stopper ring has a plurality of stopping elements arranged one behind the other in the circumferential direction of the rotor shaft, such as stopper openings, for example.